42 S. H. SCUDDER ON PALAEOZOIC COCKROACHES. 



costal margin nearly across the basal fifth of the wing. The mediastinal area is exception- 

 ally small for this genus, even if we consider, as is probable, a marginal half to be 

 destroyed ; the veins in the fragment of it are somewhat obscure, consisting of only two or 

 three parallel to each other, the lower or inner forking twice near the base and terminating 

 a little before the middle of the wing. The scapular vein suddenly bends at the end of the 

 basal fifth of the wing and runs closely parallel to the costal margin for a distance equal to 

 about half the length of the wing, and then curves somewhat rapidly to a longitudinal 

 direction, running down the middle line of the wing and terminating at its tip ; its first 

 vein, which like most of the others is deeply and simply forked, continues the direction of 

 the basal part of the stem; the last is a shoot which parts from the main stem at about the 

 middle of its longitudinal course ; the intermediate ones, to the number of five, part at equal 

 distances from one another in the oblique portion of the main stem, and are straight and 

 parallel to the direction of the basal branch. The externomedian vein parts abruptly from 

 the scapular vein shortly before the end of its basal course and runs subparallel to it, 

 diverging gently from it in the apical half of the wing and emitting, at regular and distant 

 intervals, three or four superior, gently arcuate, simple or forked longitudinal branches, 

 commencing at a little before the middle of the wing, the first branch approaching the 

 scapular vein and then continuing beside it; the area occupies only a narrow space at the 

 extremity of the inner margin. The internomedian vein parts from the scapular just 

 before the externomedian and in a nearly similar way; it runs nearly parallel to the latter, 

 but with a very straight course, to about the middle of the apical half of the wing; nor- 

 mally it probably emits four or live simple or forked branches not quite so closely crowded 

 as those of the two preceding areas; but in the specimen examined several of them spring 

 from an offshoot of the second branch which runs parallel to the main stem, the latter 

 forking once at its tip; there is also a strongly arcuate vein, close and parallel to the anal 

 furrow, which seems to be a basal branch of this vein parting from it while still amal- 

 gamated with the preceding veins. The anal furrow is deeply impressed, strongly arcuate, 

 roundly bent near the base, its apical half nearly straight, and strikes the inner margin a 

 little before the end of the basal third of the wing; owing to the basal curve the anal 

 area is nearly as broad as long, and is filled with six or seven nearly straight veins 

 of varying obliquity, some of them branched and the branches uniting irregularly with the 

 neighboring branches in a very peculiar manner, somewhat, apparently, as in III. mantidi- 

 oides. 



The fore wing only is preserved and is of a rather small size, being only 16.35 mm. long 

 and 7.2 nun. broad, or the breadth to the length as 1:2.3; all the veins and their branches 

 (excepting of course the anal furrow) are very delicate and the branches generally rather 

 closely crowded ; the surface appears to have been smooth as the interspaces are wholly 

 unbroken by any cross nervules. The wing is nearly complete, but the margin is rather 

 ragged and a considerable portion of the edge of the costal border appears to be o-one. 



From the comparatively small extent of the mediastinal area and the nearly parallel 

 veins therein this species cannot be confounded with any other form of Mylacris. 



The specimen occurred on dark grey shale, associated with ferns and leaves of Spheno- 

 phyllum Schlotheimii, and was found with the following species in the productive coal- 

 measures (or middle coal-formation) of Sydney, Cape Breton, by Mr. Richard Brown. F. G. S., 

 and communicated to me by Principal Dawson, to whose kindness I owe many similar 

 favors. 



